Municipal water companies run their mains beneath public rights of way such as streets. Normally open shut-off valves are incorporated at various locations in the mains for the purpose of isolating breaks in the mains to facilitate their repair.
These shut-off valves are usually buried several feet beneath the surface of the street and suitable access must be provided so that the valves can be manipulated. The usual practice is to cap the valve actuator with a length of access pipe which extends upwardly from the valve to a position several inches beneath the surface of the street. At street level imbedded in the pavement is a flanged cover having a removable lid.
The lid for a valve opening cover usually rests loosely on a lip in the cover. And the lids frequently are displaced either by vandals or by normal vehicular movement on the street. When this happens dirt and other debris is allowed to enter the access opening for the water valve. The access pipe leading to the valve actuator can become filled to a considerable depth with debris making it difficult to gain access to the valve actuator.
A fairly obvious solution to the problem of debris accumulation in the valve access pipe is to put a cap on the pipe just beneath the cover in the pavement. Thus, if the cover lid is displaced the cap blocks entry of debris into the valve access pipe.
With many shut-off valve installations capping the access pipe is made difficult by the fact that the opening through the cover imbedded in the pavement is smaller than the opening in the access pipe. A simple one piece cap cannot be placed on the access pipe opening because of restricted access through the cover.
Moreover, if one solves the problem of capping the access pipe through the restricted cover opening there still remains the problem of providing easy access through the cap itself to permit a tool to be extended through the access pipe to the valve actuator.